Method of making holders for drills or the like.



A. H. KNIGHT. METHOD 0F MAKING HOLDERS FOR DRILLS 0R THE LIKE.

APPLICATION FILED SEPT. 3, 1910.

Patented Oct. 31, 1911.

Vj .f/ M 35, MGM 2115@ FFIC.

ALBERT I-I. KNIGHT, OF CLEVELAND, OI-IIO.

METHOD OF MAKING HOLDERS FOR DRILLS 0R THE LIKE.

Specicaton of Letters Patent.

Patented Oct. 31, 1911.

Application led September 3, 1910. Serial No. 580,369.

To atl whom it may concern:

Be it known that I, ALBERT I-I. KNIGHT, a citizen of the United States, resident of Cleveland, county of Cuyahoga, and State of Ohio, have invented a new and useful Improvement in Methods of Making Holders for Drills or the Like, of which the following is a specification, the principle of the invention being herein explained and the best mode in which I have contemplated apply- The said invention consists of a method hereinafter fully described, and particularly set forth in the claims.

The annexed drawing and the following description set forth in detail a certain mode of carrying out my invention, the disclosed mode, however, constituting but one of various forms in which the principle of the invention may be applied, and illustrating my improved method as applied in the making of the holder shown, described and claimed in my co-pending application, Serial No. 548,326, filed March 10, 1910. y

In said annexed drawing: Figure I is a perspective of the rough blank. Fig. IIis a similar view, showing any accepted form of drift slot and cylindrical bore. Fig. III is a like perspective view after the completion of the next successive step. Fig. IV is a perspective view of a mandrel. Fig. V is a perspective view showing the mandrel inserted in its seat. Fig. VI is a perspective of the holder completed as to its exterior form. Fig. VII is a similar view of the finished holder. y

In the particular application of the method which I will now describe, the lateral drift slot holes are rst accurately drilled from both sides of the rough blank 1, and the opening 2 thereafter nished as desired. A hole 3 is next drilled through the longitudinal axis of the blank, and should extend as far as, or slightly farther than, the inner end 4 of the drift slot, as clearly shown in Fig. II.

There now being an opening of suiiicient size for the ready manipulation of other tools, a shaper can be brought into operation, and the longitudinal and complementary grooves 5 and 6, as indicated in Fig. III, cut into oppositely disposed portions of the bore. These grooves 5 and 6 compose a seat, and are, when finished to approximately the size determined upon, gradually reduced in depth as they extend toward and terminate near, the inner end 4 of the drift slot. This isy accomplished without diiiiculty by merely clamping the blank at an angle upon the table. The corresponding sides 7 and 8 of the grooves, should, of course, be as nearly parallel as possible, whereas the two oppositely disposed sides 7 and 9, or 8 and 10, may be either substantially parallel, or of like convergence with respect to each other. In Fig. III they are illustrated as substantially parallel. The bottoms 11 and 12 of these grooves are in the drawing shaped circumferentially of the axis of the hole 3, and for the obvious dual purpose of insuring proper centering and lending a more efcient bearing.

The blank is next heated so as to cause the metal to expand, and while in such heated condition the shank 13 of a mandrel having an exterior contour corresponding with that which it is desired to impart to the interior of the holder is inserted between such grooves 5 and 6, and forcibly driven into the blank, until the inner extremity 14 of the mandrel projects a suitable distance beyond the inner end 4 of the drift slot. Fig. V shows the mandrel in this position. A further relative compressive force may immediately thereafter be exerted between' the blank 1 and the shank 13 by the application of a direct compressive force upon the exterior of the blank. In this manner, as will be' apparent to those skilled in the art, that part of the bore comprising the two complementary grooves 5 and 6 may be made to conform absolutely to the shank of the mandrel, and hence necessarily to a similar flat tapered shank of a drill, or the like. The mandrel is now withdrawn before the blank has had anopportunity-` to shrink upon it. v

After the blank has become cool, the mandrel is again firmly inserted, and then accurately centered on the tail stock, while the opposite end of the blank is similarly centered on the head stock, of a lathe. The

turning of a standard taper 15 upon the exterior of the blank now becomes a simple matter. The resultant appearance of the holder after this step and the succeeding formation of the tang 16 is shown in Fig. VI. The final step following upon the second Withdrawal of the mandrel shank simply consists in securing the holder' in a lathe spindle, and reaming out the cylindrical portion of the bore, until it assumes a conical form of standard taper.

In considering this method independently of its application for a feasible manufacture of the structural conception disclosed in my co-pending application, it should be especially noted that the method positivelyT insures the exterior taper running true with respect to each of the interior tapers. The relative format-ion of the exterior taper is directly dependent vupon the previously established interior contour of the complementary grooves, and in the same manner the relative reaming of the cylindrical bore is directly dependent upon the necessarily prescribed exterior taper of the holder.

It is noted that the relative compressive force between the blank and mandrel could be effected equally well in the following reversed manner: A mandrel by having its head end likewise formed as a shank of round standard taper, would permit of this portion being fitted into the lathe spindle and thereafter the blank forcibly driven upon the other flat shanked end of prescribed contour to accomplish the same result, as should be obvious to those skilled in the art. Similarly, and following upon the turning of the exterior taper upon the blank after the mandrel has been withdrawn prior to cooling and then reinserted when both parts are entirely cool; the projecting round tapered head end of the mandrel may be centered in the same reversed manner on the tail stock of the lathe.

I-Iaving fully described my invention, what I claim and desire to secure by Letters Patent is l. The steps in the method of making' 2. The steps in the method of making holders for drills or the like, which consist in forming a bore in the blank, shaping grooves composing complementary seats in portions of the wall of said bore, heating the blank, inserting` the shank of a mandrel into such seat while in a heated condition, and finally effecting the relative compression of said blank and mandrel.

3. The steps in the method of making holders for drills or the like, which consist in forming a cylindrical bore in the blank, shaping grooves into oppositely disposed portions of the wall of said bore, heating the blank, insertino a flat mandrel between said grooves while Iieated, effecting the relative compression of said blank and mandrel, centering said mandrel on the spindle of a lathe, and finally turning the exterior of the blank to a standard taper.

4. The steps in the method of making holders for drills or the like, which consist in forming a cylindrical bore in the blank, shaping complementary grooves composing a seat in the wall of said bore, heating the blank, inserting a flat mandrel into said seat while heated, effecting the relative compression of said blank and mandrel, centering said mandrel on a lathe, turning the exterior of t-he blank to a standard taper, and finally reaming the cylindrical bore into conical form of standard taper.

5. The steps in the method of making holders for drills or the like, which consist in forming a cylindrical bore in the blank, shaping complementary grooves forming a seat in the wall of said bore, heating the blank, inserting the shank of a mandrel having an exterior contour corresponding with that which it is desired to impart to the interior of the holder into said seat while heated, effecting the relative compression of said blank and mandrel, withdrawing the shank of the mandrel prior to the cooling of said blank, inserting the shank of the mandrel into the blank after the latter has cooled, centerin said mandrel on a lathe, turning the exterior of the blank to a standard taper, and finally reaming the cylindrical bore into conical form of standard taper.

Signed by me, this 2nd day of September,

ALBERT H. KNIGHT. Attested by- CURT B. MUELLER, LYNN E. MUELLER.

Copies of this patent may be obtained for ve cents each, by addressing the Commissioner of Patents,

Washington, D. 0. 

